Production Monitoring of Multilateral Wells by Quantum Marker Systems

Reliable information about the inflow composition and distribution in a multilateral well is of great importance and an existing challenge in the oil and gas industry. In this paper, we present an innovative method for dynamic monitoring of inflow profile based on quantum marker technology in a multi-lateral well located in West Siberia. Marker systems were placed in the well during the well reconstruction by horizontal side tracking with the parent borehole remaining in production. This way of reconstruction allows development of the reservoir drainage area with a lateral hole and bringing the oil reserves from the parent borehole into production, which results in an increased flow rate and improved oil recovery rate. Placement of marker systems into parent borehole and side-track for fluid distribution monitoring allows to evaluate the flow rate from every borehole and estimate the effectiveness of performed well reconstruction. Marker systems are placed into the parent borehole as a downhole sub installed into the well completion string. For the side-track polymer-coated marked proppant was injected during hydraulic fracturing to place markers. The developed method was reliably used for an accurate and fast determination of the inflow distribution in a multi-lateral well which allows more efficient field development and also enabled us to provide effective solutions for following challenges: Providing tools for timely water cut diagnostics in multilateral wells and information for water shut-off method selection; Selecting the optimal well operating mode for effective field development and premature flooding prevention in one or both boreholes; Evaluating whether well construction was performed efficiently, and an increased production rate was achieved; Leading to a considerable economic savings in capital expenditure.

Double Casing Exit for Side-Track to Commingle Two Borehole Sizes Based Sections in One Slim Shot to Well TD

This project began when a 9-5/8" in 43.5 ppf production casing became inaccessible due to the existing cemented pipe inside, preventing further reservoir section exposure and necessitating a mechanical side-track meanwhile introducing the challenge of loosing one section and imposimg slim hole challenges. The size and weight of the double-casing made for challenging drilling, as did the eight very different formations, which were drilled. The side-track was accomplished in two steps, an 8½ in hole followed by a single long 6⅛ in section, rather than the three steps (16 in, 12¼ in, 8½ in) that are typically required. The optimal kick off point carfully located across the dual casing by running electromagnetic diagnostics, the casing collar locator, and the cement bond log. The double casing mill was carefully tailored to successfully accomplish the exit in one run. Moreover, an extra 26 ft. MD rathole was drilled, which helped to eliminate the mud motor elongation run. A rotary steerable system was utilized directly in a directional BHA to drill an 8½ in open hole building section from vertical to a 30⁰ inclination. A 7.0 in liner was then set to isolate weak zones at the equivalent depth of the outer casing (13-3/8"). Subsequently, a single 6⅛ in section was drilled to the well TD through the lower eight formations. Drilling a 6⅛ in section through eight formations came with a variety of challenges. These formations have different challenging behaviors relative to the wellbore pressure that typically leads to the drilling being done in two sections. Modeling the geo-mechanical characteristics of each formation allowed the determination of a mud weight range and rheology that would stabilize the wellbore through all eight formations. The slim, 6⅛ in, hole was stabilized with higher equivalent circulating density (ECD) values than is typically used in larger boreholes. Optimizing mud weight and drilling parameters, while managing differential sticking with close monitoring of real-time ECD, helped to stabilize the high-pressurized zones to deliver the well to the desired TD with a single borehole. This project represents the first time in Kuwait that double casings in such large sizes have been cut and sidetracked. It is also the first time these eight formations have been cut across such a smaller hole size, slim hole (6⅛ in) in a single shot. Geo-mechanical modeling allowed us to stabilize the pressurized formations and to control the ECD. The well also deployed the longest production liner in the field commingling multiple reservoirs with differnt pore pressure ramps, with excellent cement quality providing optimal zonal isolation.

Assessment of the Railroad Transport Impact on Physical and Chemical Soil Properties: The Case Study from Zduńska Wola Karsznice Railway Junction, Central Poland

Contamination of the soil and water environment with harmful substances can be associated with many activities carried out on the railway. The problem is particularly relevant to liquid fuel loading and refueling facilities as well as to increased traffic at railway junctions. Studies were conducted in the area of railway junction Zduńska Wola Karsznice in central Poland (Łódź Voivodeship). Soil samples were collected from specific research points: from the inter-railway (A), 5 m from the main track (B), from the embankment—10 m from the main track (C), and from the side track (D), at the depth of 0–5 (1) cm and 20 cm (2). The following analyses were made: granulometric composition, pH in H2O, and percent content of carbonates (CaCO3). PHEs were determined in the fractions: 0.25 ≤ 0.5 mm, 0.1 ≤ 0.25 mm, and 0.05 ≤ 0.1 mm: Pb, Cd, Cr, Co, Cu, Ni, Zn, Sr by inductively coupled plasma mass spectrometry technique (ICP-MS/TOF OPTIMass 9500). The objectives of the study were (1) to assess PHEs (potentially harmful elements) contamination of the topsoil level of railway area, (2) to determine the correlation between the concentration of PHEs and the size of the fraction, and (3) to identify the areas (places) where the highest concentrations of PHEs were recorded. Based on the studied parameters, significant differentiation in soil properties of the areas in Zduńska Wola Karsznice was found. The analyses carried out showed that the accumulation of potentially harmful elements was as follows: Cu > Zn > Sr > Pb > Ni > Cr > Co > Cd. The average concentrations of Cu, Zn, Sr, Pb, Ni, Cr, Co and Cd were 216.0; 152.1; 97.8; 64.6; 15.2; 14.4; 3.1 and 0.2 mg·kg−1 d.w., respectively. These contaminations occur in the topsoil layer of the railway embankment, which suggests a railway transport origin. The highest concentrations of PHEs were recorded in samples collected from close to the rails (inter-railway, side track), and in the embankment (10 m from the track) in the very fine sand fraction (0.05 ≤ 0.1 mm). The high accumulation index of copper, cadmium and lead in the surface layer of soil indicate their anthropogenic origin. The results presented in the paper can be used in local planning and spatial development of this area, taking into account all future decisions about ensuring environmental protection, including groundwater and soils.

Multivariant Well Placement and Well Drilling Parameters Optimization Methodology. Case Study from Yamal Gas Field

More and more oil and gas fields are moving into the third stage of development - the stage of production decline. Oil and gas operating companies are looking for the most effective ways of production stabilization and extending the period of well exploitation. The most frequently used approach of improving exhausted reservoirs performance is reducing the pace of pressure and hydrocarbons production decline by well workovers and horizontal sidetracks drilling. The most widely used type of new producing wells trajectory in low - and medium-amplitude gas fields, which include most of the Western Siberia gas reserves, is horizontal completion. According to the analysis carried out by two major Rosneft scientific centers, in oil saturated reservoirs with thickness less than 20 meters, the efficiency of horizontal wells with 300 meters length is 1.6-4 times higher than for directional wells, depending on the reservoir thickness and permeability. In gas saturated formations, the efficiency of horizontal wells performance relative to the directionally drilled wells in similar geological conditions is 3-6 times higher. As the consequence of scientifically based well performance analysis the volume of horizontal wells drilling and horizontal side track completions at the assets of PJSC "NK "Rosneft" significanty increased as for the period from 2016 to 2021, Figure 1.

Delivered Successfully an Open Hole Side-Track from Very Challenging Formation Through Very Narrow MD Window: A Case Study from Kuwait

This article presents a unique case study where operating company, Kuwait Oil Company (KOC), decided to make an attempt to perform open hole side-track through a very narrow side-track window along with other exiting conditions such as severe downhole losses and drill through very challenging formation. To deliver such project in first attempt requires very detailed planning, close coordination with various service partners such as directional drilling and cementing. Placing a good side-track cement plug in such formation was a challenge, and 2nd challenge to get kicked off from this narrow window in first attempt which was the key. In case of failure, whip stock option has to be planned as a contingency, which possess new challenging of opening a depleted zone leading to commingling low/high pressure formation which could cause a complicated problem such as borehole stability, leads to stuck pipe problem. Failure to side-track from open hole could end of planning to drill extra hole which required extra casing string to run which will put this project well over AFE and heavily impact on well objective. This open hole Side-track was planned because while drilling original hole (12 ¼" hole section) close to planned well TD, experienced complete losses. In attempt to cure the losses, LCM was pumped with no success. Performed thixotropic cement plug job for losses control. While performing thixotropic cement plug job, the cement flash set before finishing the displacement, leading to stuck string. After backing off string and fishing attempts, unable to recover the fish completely. Fish left in hole leading to only 68 ft of open hole window available to side-track where performing a cement job was impossible due to severe losses. Only way to secure the well is to try for open hole side-track. With existing sever loss situation for initiating open hole side-track was a serious challenge due to lack of side force and flow restriction to initiate the side-track. Extensive pre-job planning, peer review and risk assessment was done in coordination with various service partners to deliver such challenging side-track. A hazard analysis decision tree was established to pinpoint the risks and appropriate mitigation measures along with contingency plan put in place. A detailed side-track guidelines was shared and review with the field crew. The wellbore was successfully side-tracked through a challenging reactive shale formation in a first attempt using a customized kick-off BHA, which not only helped to avoid loss zone in side-tracked hole but also provide additional cost savings to the company. The good hole condition at the side-track point was important to enable smooth passing of the following directional BHA to achieve directional goals.

Experience of Using Continuous Production Surveillance Techniques in Multilateral Wells on Yuzhno-Priobskoye Field

This paper deals with the case of using the production surveillance inflow tracer based method in one of multi-lateral wells located in the Yuzhno-Priobskoye field. Tracer systems were placed in the well during the well construction by horizontal side tracking, and multi-stage hydraulic fracturing (MSHF) was performed, with the parent borehole remaining in operation. This technology allows developing the reservoir drainage area with a lateral hole and bringing the oil reserves remaining in the parent borehole into production, which results in an increased well productivity and improved oil recovery rate. Tracer systems are placed into the parent borehole within a downhole sub installed into the well completion. Polymer-coated proppant packs were injected during multi-stage hydraulic fracturing to deliver the tracers to the side track lateral. Dynamic production profiling was done to aid into more efficient development of complex and heterogeneous reservoirs and improve of the productive reservoir sweep ratio during the construction of multilateral wells, which enabled us to address several key problems: Providing tools for waterflood diagnostics in multilateral wells and finding an easy water shutoff method for a certain interval Assessing the efficiency of multi-stage hydraulic fracturing and elaborating the optimal treatment design Selecting the optimal mode of the multilateral well operation to prevent premature flooding in one or more laterals Evaluating whether well construction was performed efficiently, and a higher production was achieved by side tracking. Currently, the proposed first-of-its-kind solution enables the operator to obtain a set of data that can help not only significantly improve the wells’ productivity and increase the oil recovery rate, but also lead to a considerable economic savings in capital expenditure.

Using Third Interface Echo TIE Response Through Inner Casing to Enucleate the Outer Casing Geometry in 3D View

Casings can deform over the life of the well due to various reasons such as changing stress regimes, geological fault and fractures causing pinching, pressure differential created due to production, increased pressure due to injection, squeezing formations such as shale and salt, etc. A detailed casing deformation evaluation can provide insights to the operators in correlating the deformation to suitable reasons in their field. There are various methods to evaluate the innermost casing or tubing using ultrasonic and mechanical caliper measurements but there is no technology available to evaluate outer or second casing deformation without first retrieving the inner casing or tubing. This work introduces and encapsulates the novel methodology of transforming the outer or second casing third interface echo (TIE) response, obtained by advanced ultrasonic and flexural measurement inside innermost casing or tubing, into a 3D wellbore view to suitably visualize and analyze the outer or second string deformations. The work involves measuring the azimuthal radius and thickness of the innermost casing with the ultrasonic evaluation technique and computing the azimuthal annular distance between the two casings using the flexural wave TIE arrival time and its velocity in the annular fluid. The computed values are then combined to generate an array of azimuthal internal radius values of the outer or second casing and is finally converted into a 3D wellbore image for better and straight-forward visualization. To validate the methodology, a shop inspection test (SIT) was carried out where the dimensions of the inner and the outer casing were precisely measured with a mechanical caliper tool. Following that, ultrasonic and flexural measurement tool was run inside the innermost casing to obtain the response of both casings. The comparison showed a close match between the actual values and the measurements. Also, the 3D wellbore shape clearly showed the geometry of the outer string validating the methodology used in the creation of the 3D shape. The work can enable the operators to carry out time lapse outer string analysis on a periodic basis to give them early indications of any deformation in the outer or second string. This novel technique or methodology also has valuable application in plug and abandonment (P&A) where the inner tubing and casing retrieval can be hindered due to outer casing deformation. This technique can also help in designing the right drilling BHA for sidetracking based on the minimum ID of the outer pipe through which slot recovery or side-track has to be performed.

Comprehensive Operational Assessment Eliminates Significant Lost Time on a 3-Year Development Project in Nigeria

A 3 year, 23 well project drilled by a major operator in Nigeria was challenged to develop methodologies to optimize every aspect of drilling for a development project to reduce total project time and costs. The team of operator and service company personnel created an approach that systematically examined and challenged the efficiency of all tasks. They then developed and implemented innovative methods to save time by both analyzing repetitive, lengthy, or troublesome operations and challenging many status quo rig activities. The culture of continually challenging the causes of invisible lost time (ILT) that developed resulted in the creation of several critical performance improvement methodologies each of which are explained in detail. The multiple focus areas where process improvements were made included hole cleaning efficiencies, optimizing the ROP to deliver shortest well time from drilling out the casing shoe to landing the next casing, anti-collision practices to drill out conductors with a separation factor of less than 1.0, BHA design efficiencies for equipment standardization and faster make up and break down times, managing differential sticking risks, improving survey times, and developing best practices to side-track with a point-the-bit Rotary steerable system. Exact times were tracked to establish the required baselines and drilling optimization services were introduced to modify the drilling practices to reach the technical limit. The technical limit for ROP was achieved and best practices developed in this environment for effective hole cleaning, ease of tripping, and improved tripping speeds of the BHA at the end of every run saved 38.25 days over 15 wells. Average ROP's were improved by 48% in the 17 ½" section and 57% in the 12 ¼" section. The new anti-collision methodology saved 5 hours per well. BHA assembly and tool download efficiencies saved 11.47 days. Wellbore strengthening techniques prevented seepage losses and reduced stuck pipe events. Surveying improvements saved 11.78 days and new sidetracking practices saved 5 hours per sidetrack. Tasks that could be done in parallel to the critical path were identified and tasks on the critical path were performed more efficiently. ILT elimination in drilling processes saved a total of 96 days of rig time over an established performance baseline during this 23 well project. The operator set two records for the fastest drilled and completed conventional offshore wells in Nigerian history.

New Approach for Abandon and Side Track Cement Plugs in Long & High Deviated Wells

One of the biggest challenges in Oil and gas industries is placing a proper abandonment and sidetrack cement plugs in long and highly deviated wells like ERD wells. As per ADNOC offshore strategy for introducing new technology and practices to overcome operation challenges. ADNOC offshore drilling team worked together with one of the oil and gas services provider and came up with an innovative idea and technique by using available equipment and implementing a new procedures and practices to ensure well integrity by placing a long abandon cement plug in highly deviated well across hydrocarbon bearing reservoir. The new tools and technique implemented successfully in two wells X01 and X02 in one of ADNOC offshore fields. The new idea started from planning phase by working together with Services Company, where the assigned team went through all required job planning and check the proper tools to use with the best procedures. The team faced some challenges in relation to tools and equipment availability, which affected the first trial job. However, these challenges mitigated in the next job. The new technique proved advantageous by avoiding cement plug failures during abandon and sidetrack cement plug placements jobs, in optimum time and efficient way while reducing cost. This technique subsequently introduced to all ADNOC Offshore drilling teams and to be implemented in future wells.

A Challenging Drilling Campaign Unleashed a Unique Fast Drill String Recovery Methodology Eliminating Utilizing Wireline, CT and Overcome Highly Deviated String Accessibility

Stuck pipe is one of the biggest challenges in the drilling sector and is a multi-billion-dollar issue. Recovering from stuck pipe absorbs significant cost and time. Durations for stuck pipe events and recovery can be mostly variable from a few days to up to over a month to resolve. When attempts to release the stuck pipe by jarring or acid fail, the operating company and drilling contractors are left with little option but to sever the drill string and prepare for side-track operations or even abandon the hole. Traditional pipe severance methods in the event of a stuck pipe situation typically take significant time (often days, and sometimes weeks), require specialist tools, Service Hands, and are usually reliant on wireline services to deliver the severance method. In 2018, a Major Operating Company in UAE faced a challenging high-sticking Formation, which caused massive NPT, stuck of drill strings, and loss of drilled section holes. Brainstorming within the Drilling Engineering team took the campaign to the next level of pre-planning to reach deep access in the hole to be able to achieve zonal isolation by spotting cement plugs through drilling BHA, find a solution to save the hole and recover the pipes in an efficient, cheap and productive manner. An environmentally safe pre-planned solution to severe the drill string was proposed to help save the wells and allow an excellent methodology to save the wells/fields from stuck pipe risks. The engineering solution allows a fast recovery of drill pipes using a downhole tool as a part of drilling BHA, with the option to activate it if required, by dropping a smart dart and circulating with mud for a specific time to apply cut string with two option, either spotting cement with recovered BHA or lift BHA with fish neck to try to fish in the hole.